Stable Dual-Wavelength Erbium Fiber Ring Laser With Optical Feedback for Remote Sensing

In this paper, a new stable dual-wavelength erbium fiber ring laser for remote temperature measurements is proposed and experimentally demonstrated. The sensing element is composed of two fiber Bragg gratings and sensor interrogation is achieved with a dual-wavelength erbium fiber ring laser. This configuration is made by creating two symmetrical laser cavities with similar optical power. This topology allows the performance of two laser emission lines in single-longitudinal mode (SLM) and with power instability lower than 0.23 dB, and an optical signal-to-noise ratio higher than 30 dB for all the emitted wavelengths. The application of this system for remote temperature measurements has been demonstrated even though the SLM regime cannot be maintained.